Impact of zeolite and nitrogen application on nitrogen use efficiency, growth and yield of maize (Zea mays L.)

Nitrogen (N), an essential nutrient for growth and development of plants, is added to agricultural fields to boost crop yields. Major concern in modern agriculture to account for maximum nutrient use efficiency, improve the soil fertility and prevent groundwater pollution. Environmental and economic challenges due to nitrogen application in agricultural have increased regard to nitrogen use efficiency (NUE). Improving the nitrogen use efficiency, which is the fraction of the applied fertilizer nitrogen taken up by a plant for its physiological and growth purposes, is one of the strategies for reducing N loss in agriculture. With the continued escalating costs of inorganic fertilizers, NUE in field crops should be enhanced to reduce production costs. Therefore, it is essential that appropriate N fertilizer management practices are adopted to optimize the use of applied N in cropping systems. NUE and better plant growth are related to soil’s physico-chemical traits. In this context, the application of soil amendments, such as zeolie, has great importance for the reclamation of soil properties and improve plant growth. Natural zeolites are naturally occurring, hydrated aluminosilicates with and being considered as good soil amendment for minimizes N losses and increase NUE. Therefore the objective of this study was investigating the effect of different levels of clinoptilolite zeolite and nitrogen fertilizer on the efficiency of nitrogen use, growth and yield of maize (Zea mays L.) in field conditions.

This study carried out in field condition as a split-plot arrangement based on randomized complete blocks and in three replications, at the University of Kurdistan research farm in Dehgolan. The experimental treatments include the application of clinoptilolite zeolite at four levels (0, 5, 10 and 15 ton ha-1) as the main plot and the application of nitrogen at five levels (0, 50, 100, 150 and 200 kg N ha-1) as the sub-plot. Urea fertilizer was used to supply the required nitrogen.
Maize cultivation (KSC 260 cultivar) was done in 2021. At the end of cultivation season, harvest was done from each plot, and some plant growth traits (leaf area, cob length and cob diameter), leaf N concentration, yield components (grain number in cob, raw number in cob and grain weight in cob), and grain yield were measured. In addition, the NUE was calculated. In order to investigate the effect of zeolite on soil nitrogen status, soil samples were collected from plots after harvest, and cation exchange capacity (CEC), and total soil nitrogen (TN) were measured. Analysis of variance (ANOVA) was performed using SAS program version 9.4 (SAS Institute, Cary, NC). Significant differences of the mean values (P <0 .05 for F-test) were determined by Duncans’s Multiple Range test.

The results showed that as a result of the application of 10 and 15 ton zeolite ha-1, the soil cation exchange capacity the soil total nitrogen concentration, leaf nitrogen concentration, leaf area index ,cob length, grain yield and nitrogen use efficiency increased significantly. The results showed that the highest leaf N concentration, plant growth indices, grain yield and yield omponents was observed in the treatments of co-application of 150 and 200 kg N ha-1 with 10 and 15 ton ha-1 of zeolite. There was no significant difference between the grain yields in these treatments. The results also indicated that Moreover, nitrogen use efficiency decreased with increasing nitrogen application levels. The nitrogen use efficiency (NUE) in the 150 kg N ha-1 treatment was significantly higher than 200 kg N ha-1 treatment. The results demonstrated that there was no significant difference between two nitrogen fertilizer levels (150 and 200 kg N ha-1) positive effects on grain yield. The improved maize growth and enhanced grain yield induced by zeolite amendment were related to the increase in soil CEC, soil N status, N uptake in plant, as well as probably improved soil nutrient availability and physicochemical propertis. Leaf N concentration (56.6), leaf area index (56.5%), cob length (21.5%), leaf nitrogen concentration (56.6%), grain weight in cob (61.8%), grain number in cob (41.6%) and grain yield (38.6%) in the plant were significantly higher than control treatment.

It could be concluded that application of potassium sulfate fertilizer results In general, it can be concluded that the combined use of zeolite (at the level of 10 ton ha-1) and nitrogen (150 kg ha-1) can be a suitable solution for improving corn yield and increasing the nitrogen use efficiency (NUE).